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Topic: +18 AFMA out of the box....return? (Read 5751 times)

Hi all, I got bored of waiting for a siggy 50 'A' so I bit and bought the canon 50mm 1.4 as I didn't want focus issues.Lawl.I've got it and it seemed really soft, and tried an afma. It's at +18.My question is : AFMA is supposed to be for dealing with tolerances and mishaps in the field. I know i'm not going to get a perfect 0, but if say, it gets knocked +3, i'm going to have a 1.4 I can't use.Do I take it back or send it to CPS under warranty?

My 35mmL was +2 on my 5D MK II and +14 on my 1D MK III. I sent it to CPS and they calibrated the lens to their reference 1D MK III and its been nearly right on for every camera since then, including another 5D MK II, two 5D MK III's, and a 1D MK IV.

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I recently bought a used 16-3L II and it seemed soft at first. After a quick AFMA, Focal suggested +12/13 on both ends. It was tested under very good lighting conditions(+15EV) and on a stable tripod. That AFMA made it a lot better though. But do these extreme values imply something is seriously wrong with the lens and need to be checked/calibrated?

I recently bought a used 16-3L II and it seemed soft at first. After a quick AFMA, Focal suggested +12/13 on both ends. It was tested under very good lighting conditions(+15EV) and on a stable tripod. That AFMA made it a lot better though. But do these extreme values imply something is seriously wrong with the lens and need to be checked/calibrated?

if I sell a lens, I don't want someone with an xti complaining I sold them a bad lens because they can't do afma.

I recently bought a used 16-3L II and it seemed soft at first. After a quick AFMA, Focal suggested +12/13 on both ends. It was tested under very good lighting conditions(+15EV) and on a stable tripod. That AFMA made it a lot better though. But do these extreme values imply something is seriously wrong with the lens and need to be checked/calibrated?

if I sell a lens, I don't want someone with an xti complaining I sold them a bad lens because they can't do afma.

There's no problem with a big adjustment, per se, as long as it's 20 units or less. The problem is when you change upi your gear. If your lens needs +18 on your current body, what if you get a new body that is off in the same direction - now, 20 units of adjustment isn't enough.

lens is -15 and the body is +4 making the total adjustment 19 notches till AF is perfect.

Then you get a new body and the same lens. The lens is still at -15, but the new body is at +9, so now you are at 24 notches till perfect.

And if I'm wrong, please feel free to correct me out there.

So it is really about the lens, because let's say your body is +15 and your lens is +13, then you only have 2 in total difference. So when you sell it to someone without AFMA, their body is -10 and the lens is +13 for a total difference of 23... which could be a real problem.

So my presumption is that you want to make sure that you are identifying whether it is a combination of body + lens which is getting the high number or whether it is the lens itself.

There's no problem with a big adjustment, per se, as long as it's 20 units or less. The problem is when you change upi your gear. If your lens needs +18 on your current body, what if you get a new body that is off in the same direction - now, 20 units of adjustment isn't enough.

lens is -15 and the body is +4 making the total adjustment 19 notches till AF is perfect.

Then you get a new body and the same lens. The lens is still at -15, but the new body is at +9, so now you are at 24 notches till perfect.

And if I'm wrong, please feel free to correct me out there.

So it is really about the lens, because let's say your body is +15 and your lens is +13, then you only have 2 in total difference. So when you sell it to someone without AFMA, their body is -10 and the lens is +13 for a total difference of 23... which could be a real problem.

So my presumption is that you want to make sure that you are identifying whether it is a combination of body + lens which is getting the high number or whether it is the lens itself.